Synthesis and luminescence properties of novel deep red emitting phosphors Li2MgGeO4:Mn4+

Novel deep red phosphor Li2MgGeO4:Mn4+ is synthesized by high temperature solid state reaction method in air. The strongest PL band peaking at similar to 671 nm in the range of 600-750 nm is due to the E-2 -> (4)A(2) transition of Mn4+ ion and the PLE spectra shows broad band peaking at similar to 323 within the range 220-550 nm owing to the (4)A(2) -> T-4(1) transitions of Mn4+ ion. The optimum Mn4+ doping concentration is about 0.4 mol.%. The luminous mechanism is explained by Tanabe-Sugano diagram of Mn4+ ion. The results indicate that red phosphor Li2MgGeO4:Mn4+ is a beneficial phosphor for use in white light-emitting-diodes (LEDs).